C updating an access data base

21 Dec

This may also allow, in many cases, to use the memory=true setting, whilst it was impossible before.

It should be set to a value close to the average size of OLE instances.

If there are no active connections for the inactivity Timeout period (in minutes) HSQLDB will be temporarily shut down and any filesystem resources will be released. keep Mirror (since UCan Access 2.0.2): keeps the HSQLDB mirror database after the VM ends so it can be reused by subsequent VM processes. In other words, using this parameter, the time-expensive process of creating and populating the database hsqldb (with memory=false), is executed only once. - If the access database is modified by a different program (so not using UCan Access) after the HSQLDB creates the mirror database, UCan Access recreates and repopulates the whole mirror database for avoiding unchecked misalignments. prevent Reloading (since UCan Access 3.0.0): optimize the reloading of db instances.

If and only if you're sure that your db can be accessed by the MS Access GUI and just one JVM instance (using UCan Access), you can use the connection parameter .

It avoids the data being reloaded when they aren't actually changed by the GUI.

jackcess Opener (since UCan Access 0.0.2): in order to use Jackcess Encrypt extension, you can specify a class that implements the net.

lob Scale (since UCan Access 2.0.9.4): to optimize memory occupation when a relevant percent of memory occupation is for OLE (BLOB) data.

Notice that you must use UCan Access 2.x.x with jackcess-encrypt-2.x.x and all related dependecies package your Package.example; import Jackcess Opener Interface; //imports from Jackcess Encrypt import com.healthmarketscience.jackcess. Ucanaccess Driver"); Connection conn= Driver Connection("jdbc:ucanaccess:///opt/prova1.mny;jackcess Opener=your Package.example. For old UCan Access versions (0.x.x,1.x.x) Jackcess Opener Interface should be implemented in a different way, because of the jackcess API changes from jackcess1 to jackcess2. Crypt Codec Provider; import com.healthmarketscience.jackcess. You should escaping identifiers including a blank space using square brackets or backtick character (`).

Crypt Codec Provider; import com.healthmarketscience.jackcess. Also you shold escaping identifiers that equal a SQL keyword (e.g. SQL Keywords are: ALL, AND, ANY, AS, AT, AVG, BETWEEN, BOTH, BY, CALL, CASE, CAST, COALESCE, CONSTRAINT, CORRESPONDING, CONVERT, COUNT, CREATE, CROSS, DEFAULT, DISTINCT, DO, DROP, ELSE, EVERY, EXISTS, EXCEPT, FOR, FROM, FULL, GRANT, GROUP, HAVING, IN, INNER , INTERSECT, INTO, IS, JOIN, LEFT, LEADING, LIKE, MAX , MIN, NATURAL, NOT, NULLIF, ON, ORDER, OR, OUTER, PRIMARY, REFERENCES, RIGHT, SELECT, SET, SOME, STDDEV_POP, STDDEV_SAMP, SUM, TABLE, THEN, TO, TRAILING, TRIGGER, UNION, UNIQUE, USING, USER, VALUES, VAR_POP, VAR_SAMP, WHEN, WHERE, WITH, END.

Statement st =conn.create Statement(); st.execute("CREATE TABLE example1 (id COUNTER PRIMARY KEY,descr text(400), number numeric(12,3), date0 datetime) "); ..execute("create table dkey(c counter , number numeric(23,5) , PRIMARY KEY (C, NUMBER) "); ..execute("create table dtrx(c text , number numeric(23,5) , unique (C, NUMBER)) "); ..execute(" CREATE TABLE Parent( x autoincrement PRIMARY KEY, y text(222))"); ..execute(" CREATE TABLE Babe( k LONG , y LONG, PRIMARY KEY(k,y), Result Set rs=st.execute Query("SELECT IIf(descr='Show must go off','tizio','caio&sempronio'&'&Marco Amadei'&' '& Now() & RTrim(' I''m proud of you ')) FROM example1"); // Domain Aggregate functions: Result Set rs=st.execute Query("select id, DCount('*','t234','1=1') from t234"); More complete examples of access functions implementation are shown in the net. The following functions are already implemented: ASC, ATN, CBOOL, CCUR, CDATE, CDBL, CDEC, CINT, CLONG, CSIGN, CSTR, CVAR, DATEADD, DATEDIFF, DATEPART, DATE, DATESERIAL, DATEVALUE, FIX, FORMAT, IIF, INSTR, INSTRREV, ISDATE, ISNUMERIC, INT, Is Null, LEN, MID, MONTHNAME, NOW, NZ, PARTITION, SIGN, SPACE, SQR, STR,, STRING, STRCOMP, STRCONV, STRREVERSE, SWITCH, RND, TIME, TIMESERIAL, VAL, WEEKDAY, WEEKDAYNAME; Aggregate and Domain Functions: FIRST, LAST, DCOUNT, DAVG, DSUM, DMAX, DMIN, DFIRST, DLAST, DLOOKUP.

Financial Functions(since UCan Access 2.0.7.1): PMT, NPER, IPMT, PPMT, RATE, PV, FV, DDB, SYD, SLN.